require 'rubygems'

require 'eventmachine'

def GetPOSTCommand(query)
    if query[0..4] == 'POST '
        if query.scan("\r\n\r\n").size > 0
            return query[5..-1].slice(/^\S+(?= HTTP\/1.1\r\n)/i)
        end
    end

    return nil
end

def GetGETCommand(query)
    if query[0..3] == 'GET '
        if query[query.bytesize-4..query.bytesize-1] == "\r\n\r\n"
            return query[5..-1].slice(/^\S+(?= HTTP\/1.1\r\n)/i)
        end
    end

    return nil
end


def GetPOSTContentLength(query_header)
    hdr_contentl =  query_header.slice(/\r\nContent-Length: \d+(?=\r\n)/i)
    if hdr_contentl
        return hdr_contentl.split(' ')[1].to_i
    end

    return 0
end

def GetHost(query_header)
    hdr_contentl =  query_header.slice(/\r\nHost: \S+(?=\r\n)/i)
    if hdr_contentl
        return hdr_contentl.split(' ')[1]
    end

    return nil
end

def GetPOSTContent(query)
    header_size = query.split("\r\n\r\n")[0].bytesize+4
    return query[header_size..-1]
end

def GetPOSTHeader(query)
    return query.split("\r\n\r\n")[0] + "\r\n\r\n"
end

def GetPOSTBoundary(query_header)
    hdr_contentt = query_header.slice(/\r\nContent-Type:\s+multipart\/form-data;\s+boundary\=\S+(?=\r\n)/i)
    if hdr_contentt
        return hdr_contentt.split('boundary=')[1]
    end

    return nil
end

def ParsePart(part)

    if part[0..3] == "--"
        return nil
    end

    size = part.bytesize
    if part[size-2..size-1] != "\r\n"
        return nil
    end

    part = part[0..size-3]

    part_header = part.slice(/^\r\nContent-Disposition:\s+form-data;.+?name=\S+.*?(\r\n.*?)?\r\n\r\n/i)
    if part_header == nil
        return nil
    end

    result = Hash.new


    result["name"] = part_header.slice(/name=\"\S+\"/i).split("=")[1]
    result["data"] = part[part_header.bytesize..-1]
    filename = part_header.slice(/filename=\"\S+\"/i)
    if filename != nil
        result["filename"] = filename.split("=")[1]
    end

    return result
end

def ParsePOSTMultipart(query_content, boundary)

    parts = query_content.split("--"+boundary)

    result = Array.new
    i = 0
    parts.each do |cpart|
        pp = ParsePart(cpart)
        if pp != nil
            result[i] = pp
            i += 1

        end
    end
    return result
end

def ParsePOST(query, fullparse = true)

    cmd = GetPOSTCommand(query)
    if cmd == nil
        return nil
    end


    result = Hash.new

    result["type"] = "POST"
    result["command"] = cmd
    qheader = GetPOSTHeader(query)
    result["content-length"] = GetPOSTContentLength(qheader)
    #puts "ParsePOST: cont-len #{result["content-length"]}  qheader.bytesize = #{qheader.bytesize} ( #{qheader.size})  query.bytesize = #{query.bytesize} (#{query.size})"
    result["host"] = GetHost(qheader)
    result["completed"] = (qheader.bytesize+result["content-length"] <= query.bytesize)

    if fullparse
        result["content"] = GetPOSTContent(query)

        result["boundary"]  =GetPOSTBoundary(qheader)
        if result["boundary"] != nil
            result["multipart"] = ParsePOSTMultipart(result["content"], result["boundary"])

        end

    end

    return result
end

def PreParsePOST(query)

    return ParsePOST(query, false)
end

def IsQueryCompleted(query)

    command = GetGETCommand(query)
    if command != nil
        result = Hash.new
        result["type"] = "GET"
        result["completed"] = true
        result["host"] = GetHost(query)
        result["command"] = command
        return result
    end

    result = PreParsePOST(query)
    if result != nil
        if result["completed"]
            result = ParsePOST(query)
        end
        return result
    end

    return nil
end

def SaveData(data)
    b = rand
    a = "#{b}"
    time1 = Time.new
    newfilename = time1.inspect + "_" + a + "_" + ".dat"
    puts "Save to file #{newfilename}"
    File.open(newfilename, 'w'){ |file| file.write data }
end

#Здесь проверяем валидность URI и host
def CheckURL(host, uri)
    # URL = host+uri
    puts "URL : #{host}#{uri}"
    #можно host проверить, а можно не проверять
    return uri == "handler.php"
end

#Здесь обрабатываем GET-запросы
def HandleGET(query_data)
    puts "GET QUERY============="

    sz = query_data["command"].bytesize
    return "HTTP\/1.1 200 OK\r\nServer: huy\r\nContent-Length: #{sz}\r\n\r\n"+query_data["command"]
end

#Здесь обрабатываем POST-запросы
def HandlePOST(query_data)
    puts "POST QUERY============="
    puts query_data["command"]
    if query_data["boundary"] != nil

        # ПРИШЁЛ MULTIPART-FORM_DATA
        puts "reveived multipart"
        # ВЫВОДИМ и сохраняем все файлы пришедшие в multipart
        query_data["multipart"].each do |descr|
            puts descr["name"]
            puts descr["filename"]
            SaveData(descr["data"])
            innerPOST = ParsePOST(descr["data"])
            # если пост в посте то уведомляем об этом
            if innerPOST != nil
                # внутри мультипарта пришёл POST
                puts "reveived POST in multipart"
                puts "URL = #{innerPOST["host"]}#{innerPOST["command"]}"

            end
        end
    else
        innerPOST = ParsePOST(query_data["content"])
        if innerPOST != nil
            # ПРИШЁЛ ПОСТ В ПОСТЕ
            puts "reveived POST in POST"
            puts "URL = #{innerPOST["host"]}#{innerPOST["command"]}"
        end
    end
    puts "POST QUERY========= END"

    return "HTTP\/1.1 200 OK\r\nServer: huy\r\nContent-Length: 8\r\n\r\nSUCCESS!"
end

class EchoServer < EventMachine::Connection

    def post_init
        puts "connection"
        @query_buffer = ""
    end

    def receive_data data

        @query_buffer << data

        q = IsQueryCompleted(@query_buffer)
        if q != nil
            #puts "valid HTTP query"
            if q["completed"]
                #puts "completed HTTP query"
                response =  ""
                if CheckURL(q["host"], q["command"])
                    if q["type"] == "GET"
                        response = HandleGET(q)
                    elsif q["type"] == "POST"
                        #puts "completed HTTP POST"
                        response = HandlePOST(q)
                    end
                else
                    response = "HTTP/1.1 400 Bad request\r\nServer: huy\r\n\r\n"
                end

                if response != ""
                    #puts "response exist"
                    #puts response

                    send_data(response)
                end
                close_connection_after_writing
            else
                discard = true
                # обрабатываем только POST, ибо GET всегда приходит одним пакетом

                #проверяем нормальный ли это POST запрос и узнаем разрешённый ли у него URI
                pq = PreParsePOST(@query_buffer)
                if pq != nil

                    if CheckURL(pq["host"], pq["command"])
                        #puts "not completed. wait full query..."
                        discard = false
                    end
                end


                if discard
                    #puts "invalid POST request disconnect"
                    send_data("HTTP/1.1 400 Bad request\r\nServer: huy\r\n\r\n")
                    close_connection_after_writing
                end
            end
        else
            #puts "invalid request header disconnect"

            send_data("HTTP/1.1 400 Bad request\r\nServer: huy\r\n\r\n")
            close_connection_after_writing
        end
    end

    def unbind
        puts "connection end"
    end
end

EventMachine::run {
    EventMachine::start_server "192.168.0.1", 1420, EchoServer
}